Focused Acoustic Transducer for In-Line CMP Fluid Cavitation
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Solution Overview
Problem
The formation of particle clusters in chemical mechanical polishing (CMP) process fluids leads to filter plugging and surface scratches, and the generation of reactive oxygen species (ROS) is inefficient due to the need for high-power acoustic energy delivery close to the point of use.
Innovation Solution
An in-line focused acoustic energy transducer with a resonator and piezoelectric crystal is used to deliver focused acoustic energy into the fluid passageway, breaking up particle clusters through cavitation and generating ROS by focusing acoustic energy near the point of use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-power acoustic energy is delivered to generate reactive oxygen species, then ROS generation effectiveness is improved, but device complexity and energy consumption increase
Solution Approach 1:
The acoustic energy delivery system is segmented into modular components: a piezoelectric crystal transducer, a resonator with specific geometry, and a fluid passageway system. This segmentation allows each component to be optimized independently while maintaining overall system effectiveness for ROS generation.
Solution Approach 2:
The resonator incorporates a curved surface that focuses acoustic energy into a concentrated beam. This curvature enables precise targeting of the acoustic energy to the fluid passageway, improving ROS generation efficiency while reducing the overall power requirement and system complexity.
2Productivity
If acoustic energy is focused near the point of use, then process fluid treatment effectiveness is improved, but manufacturing precision requirements increase
Solution Approach 1:
The resonator's curved surface is designed with specific geometric parameters that naturally focus acoustic energy into a tight beam. This geometric focusing mechanism is more robust to manufacturing tolerances than alternative focusing methods, as it relies on the overall shape rather than precise positioning of multiple components.
Solution Approach 2:
The resonator acts as an intermediary component that transforms the acoustic energy from the piezoelectric crystal into a focused acoustic beam. This intermediary structure simplifies the precision requirements by providing a geometric pathway for energy focusing, reducing the need for ultra-precise alignment between the crystal and the fluid treatment zone.
3Manufacturing precision
If particle clusters are broken up using cavitation, then CMP process quality is improved, but energy consumption increases
Solution Approach 1:
The system applies acoustic energy selectively to the fluid passageway where particle clusters are most concentrated, rather than treating the entire fluid volume. This partial action approach breaks up clusters effectively at the critical location while minimizing overall energy consumption.
Solution Approach 2:
The curved resonator surface focuses acoustic energy into a concentrated beam that targets particle clusters precisely. This focusing effect increases the local intensity of acoustic cavitation where needed, improving cluster breakdown efficiency while reducing the total acoustic power required compared to diffuse energy distribution.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents particle clumping and enhances CMP process effectiveness by breaking up clusters and generating ROS efficiently, improving surface quality and process efficiency.
Implementation Method 1
A crystal for generating acoustic energy is attached to the solid outer structure
Implementation Method 2
The resonator is comprised of a material that transmits the acoustic energy through the resonator and includes a curved surface that focuses the acoustic energy
Implementation Method 3
The focused acoustic energy is concentrated in the fluid passageway and causes cavitation in the fluid in at least part of the fluid passageway
Implementation Method 4
The cavitation in the fluid is used in two ways. First, the energy released during cavitation can be used to break up clumps of particles that form in the process fluid
Implementation Method 5
Second, the energy released during cavitation can be used to generate reactive oxygen species (ROS) in the process fluid
Data Source
AI summary
An acoustic energy tool comprising a crystal for generating acoustic energy when a volage is applied to the crystal, and a resonator. The resonator has a solid outer structure with the crystal being attached to the solid outer structure, with the resonator being comprised of a material that transmits the acoustic energy through the resonator. The tool includes a curved surface that focuses the acoustic energy being transmitted through the resonator and a fluid passageway that extends through the resonator for allowing a fluid to flow through the resonator. The acoustic energy being focused by the curved surface is concentrated in the fluid passageway so that it causes cavitation of the fluid in at least part of the fluid passageway. The cavitation of the fluid is used to break up clumps that form in the fluid or to generate reactive oxygen species.